Finding the Fourth Proportional to 9,890.74, 13,647.90 and 5,642.38

Step by Step Solution

1. Step 1: Write the proportion equation
   9,890.74 : 13,647.90 = 5,642.38 : x
2. Step 2: Convert to fraction form
   9,890.74/13,647.90 = 5,642.38/x
3. Step 3: Cross multiply
   9,890.74x = 13,647.90 × 5,642.38
4. Step 4: Simplify right side
   9,890.74x = 77,006,638.00
5. Step 5: Solve for x
   x = 77,006,638.00/9,890.74
6. Step 6: Final answer
   x = 7,785.73